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View Full Version : Car wont idle after new TB and adaptation



blacksails192
03-21-2015, 04:02 PM
So i had an old thread on this but it was getting lengthly so im going to start a new one. Backstory I had a check engine light for a lean fault and a high idle. Brought my car to a shop with a vagcom and they diagnosed the issue as a bad throttle body. I bought a new TB and installed it and the car ran very poorly. I wasnt aware you had to perform a TB adaptation on a DBW car (98 a4 1.8t). So i ended up buying a laptop and a vagcom set up. Finally comes and i perform the throttle body adaptation and it says it performed successfully. Moment of truth... i start the car and it idles for 2 seconds then dies. Start the car again and try giving it throttle and it bogs out again. I can smell tons of fuel. Car has a brand new MAF sensor. So i unplug the MAF and the car will idle but still is rough when i give it gas. Try swapping out another known good throttle body and the same thing... Car cannot hold idle. Im at a total loss here, the car is acting like it has a massive leak but i didnt touch any vac lines. Does anyone have any ideas to look for or a similar experience?

woolveren
03-21-2015, 04:18 PM
I told you that you really don't need VagCom to do a TB adaptation. Anyway, this sounds like bad coils or plugs..

blacksails192
03-21-2015, 04:40 PM
I told you that you really don't need VagCom to do a TB adaptation. Anyway, this sounds like bad coils or plugs..

the car drove great prior to swapping tb aside from a high idle. I dont see how the coils or plugs would have just went bad while it was sitting

ricekikr
03-21-2015, 11:45 PM
Dbc.

Did you reset the trims? It could still be rich from the previous leak. Also do a boost leak test, could have another leak.